Drilling rigs have traditionally used immoveable derricks to support hoists on rigs. These derricks have significant safety issues in that equipment or structural elements can become detached and fall on worker's heads. Also, the hoisting action is subject to pitch and yaw of the vessel causing the equipment to become dangerous. A need has existed for a tower with safety advantages that can be disposed on a moveable and pivotable cantilever, particularly for jack-up rigs that have an ability to handle tubulars.
In addition, new emerging technologies such as casing and continuous tubular, or “coiled tubulars”, drilling techniques are now ready for commercial application. These techniques, however, are usually not used because there are high costs associated with integrating such equipment into traditional lattice derricks or masts.
A need, therefore, exists for a tower designed effectively use casing and continuous tubular technologies in order to reduce the cost of developing oil and gas reserves.